Yellowstone National Park South Entrance, Yellowstone visitation

UUSS Registers Over 1200 Quakes in Yellowstone Earthquake Swarm

The University of Utah Seismograph Stations (UUSS) continues to monitor the Yellowstone earthquake swarm, with over 1,200 quakes registered this year.

1,284 quakes have been registered as of 9:45 MDT July 19th. 2017. The swarm began June 12th, 2017.

We previously reported a 4.5 magnitude quake rattled West Yellowstone and Gardiner, Montana June 16, 2017. It was the largest quake in the region since March 2014, when a 4.8 magnitude quake struck the same area.

A few days later, we reported over 460 quakes had been registered in and around Yellowstone. Indeed, 2014 saw a noticeable uptick in earthquake activity, similar to the trend this year.

According to a UUSS press release, most of the quakes in the Yellowstone earthquake swarm have been minor in nature. The figures mentioned in the paragraph are below, courtesy of UUSS:

The swarm began on June 12th, 2017 and, as of 09:45 MDT on July 19th, 2017, is composed of 1,284 events with the largest magnitude of ML 4.4 (MW 4.4) (Figure 1). The swarm consists of one earthquake in the magnitude 4 range, 7 earthquakes in the magnitude 3 range, 105 earthquakes in the magnitude 2 range, 407 earthquakes in the magnitude 1 range, 736 earthquakes in the magnitude 0 range, and 28 earthquakes with magnitudes of less than zero. These events have depths from ~0.0 km to ~14.0 km, relative to sea level. At the time of this report, there were 125 felt reports for the M4.4 event that occurred on June 16, 2017 at 00:48:46.94 UTC (June 15, 2017 at 18:48:46.94 MDT). The M4.4 event has an oblique strike-slip moment tensor solution (Figures 1 & 2). In addition, four other earthquakes in the swarm have been reported felt.

Figure 1. Location of the earthquakes that are part of the swarm as of July 19, 2017 at 09:45 MDT (red symbols).
Figure 1. Location of the earthquakes that are part of the swarm as of July 19, 2017 at 09:45 MDT (red symbols).

 

Figure 2. Moment Tensor solution for the M4.4 event showing the fit between data (black) and synthetics (red dashed).
Figure 2. Moment Tensor solution for the M4.4 event showing the fit between data (black) and synthetics (red dashed).

 

In addition, you can see a video of registered earthquake activity at the swarm’s hub below, courtesy of UUSS.

Earthquakes are a common occurrence around Yellowstone National Park, owing to its proximity to a fault line. According to UUSS, quakes “comprise about 50% of the total seismicity in the Yellowstone region.” Indeed, most tremors around Yellowstone go unnoticed. If you do notice any quake activity around Yellowstone, please send a tip to the U.S. Geological Survey.

UUSS will continue to monitor the Yellowstone earthquake swarm and provide updates as needed.

About Sean Reichard

Sean Reichard is the editor of Yellowstone Insider and author of Yellowstone Insider For Families 2017.

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